Mass spectrometry (MS) is the choice method for complex protein sample analysis. This proposal requests the ABI QSTAR XL hybrid mass spectrometer. This vastly improved instrument contains the capabilities for both Matrix- Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) as well as an Electrospray Ionization Tandem Mass Spectrometer [ESI-MSn] to assist researchers at the Finch University of Health Sciences/Chicago Medical School (FUHS/CMS) in the areas of protein identification/characterization and proteomics/functional genomics. Currently, there is no MS capability at FUHS/CMS to satisfy the growing and urgent need for analysis of complex protein samples. The purchase of the hybrid mass spectrometer is being requested in conjunction with the establishment of the "Mass Spectrometry Core Facility", part of the Midwest Proteome Center, a unique infrastructure in the Chicago/Milwaukee region. Dr. Marc J. Glucksman, a recent recruit to CMS to establish a proteomics center, will head the MS facility. As described in the application, 14 investigators from 6 different departments on campus, funded by 7 different institutes at the NIH have a specific need for this equipment. Indeed, due to the lack of an instrument on campus, several investigators are currently forced to collaborate or contract with other institutions/companies to pursue their research goals, a situation often resulting in long delays, lower resolution data and hindered productivity. Thus, the purchase of the QSTAR XL mass spectrometer, in conjunction with the recruitment of additional faculty to establish the core facility, will have a major impact on biomedical research at CMS. A detailed organizational plan is described for efficient management and use of the instrument. The University has committed cost-sharing support for five years including the costs of setup, installation, equipment maintenance, support personnel, and a facility manager. The Principal Investigator has garnered world experts as members of the External Advisory Board of the facility, and an Internal Advisory Committee, as specified in the proposal. The establishment of this versatile MS core facility and the purchase of the instrument are essential to the continuing expansion and enhancement of the basic research programs on the FUHS/CMS campus. This proposed grant will allow these investigators and others to enhance their research in structural biology, neuro degenerative diseases, drug addiction, cardiovascular disorders, and infectious diseases with an in-house core analytical facility. The resulting work has practical application towards diagnosis, prevention, gene product discovery and validation.